The invention relates to a plug connector having an insulation body which has an essentially rectangular cross-section. The body has an upper side with a plurality of electric contact tracks which are arranged to lie alongside one another in one plane, to run in the plug-in direction and, when the plug connector is joined to a mating connector, to cooperate with the corresponding contact springs of the connector, which springs lie alongside one another, and produce an electric contact.
Plug connectors of this type are known, and are of interest, in particular in conjunction with the standardized USB (Universal Serial Bus) design which is the aim of several computer manufacturers. Rather than, as has hitherto been the case, peripheral devices being connected to a PC via individual, parallel connections using separate, and often different, plug connector systems, this new bus system makes it possible for the peripheral devices to be connected, essentially in series, to a common bus line, which is connected directly to a printed circuit board (motherboard) of the PC via a standardized socket on the housing of the PC. The plug-in appearance of the printed circuit board socket or receptacle is essentially already defined by a specification and has four strip-like contact springs which lie alongside one another in one plane and, when the bus connector or plug is plugged in, cooperate with the four contact rails or tracks lying alongside one another in the plug and produce the electric contact. The contact springs are arranged in the socket connector in an insulation body which is essentially designed as a plastic tongue with a rectangular cross-section, and the spring are bent over in their rear region to form connecting legs which project downwards and can be plugged into contact holes in the printed circuit board. Connector and mating connector are normally provided with a metallic screening shroud or housing. Two latching hooks are provided in the top and bottom region of this shroud and the two latching hooks engage in recesses on the screening housing of the matching mating connector and produce the earthing or grounding contact and the retaining forces when the plug is pulled out.
It is generally the case with plug connectors that the contact elements of the two components to be plugged together move towards one another in the plug-in direction during the plugging-in-operation and move away from one another along the plug-in direction during the drawing-apart operation. Outside the end position, the contact elements may move either with or without contact with one another. In this arrangement, it is fundamentally desirable to prevent the contact areas from being exposed to possible damage or contamination. In the case of the plug connector known from the specification, recesses for the contact tracks, in which the latter are retained, are provided in the insulation body. Each recess forms a closed front on the plug-in side, and the recesses are open towards the upper side. In the case of this conventional plug connector design, it is unavoidable that the contact springs of the socket connector are initially moved over the front region of the insulation body of the plug when being plugged in. This presents the risk of non-conducting plastic material coming into contact with the contact areas and accelerating the wear or abrasion gold abrasion of the high-quality-plated contact areas, which are gold plated. This can increase the contact resistance at the interfaces of the plug connector system to such an extent that the signal transmission is impaired. Sharp-edged contact of the contact elements can also lead to undesirable abrasion of the gold coating.